Cyclone III output termination for 3.3V IO standards

The restriction for 3.3V IO standards applies to higher output currents. In the range, where external series resistors comes into play, it doesn't provide less adjustment granularity as previous types, e.g. Cyclone or Cyclone II.

To match higher trace impedances, e.g. 70 ohm, you'll need series resistors as before.

Obviously Altera tries to reduce the permitted current level for 3.3V IO standards, which can be seen as a concession to 65 nm technology. Interestingly, newest Cyclone V family has re-enabled a 16 mA current strength for 3.3V LVTTL.

With Cyclone III, Altera has started to emphasize the problem of signal overshoots conflicting with maximum ratings. You'll find "watch your step"-like warnings allover the documents. Taking a closer look at overshoots occuring in some designs, it's understandable somehow.